.gridlines {
  width: inherit;
  height: inherit;
  position: relative;
  z-index: 1;
}

.row-line,
.col-line {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  display: flex;
}

.row-line {
  flex-direction: column;
}

.row-line>div,
.col-line>div {
  border: 1px solid #6f6c6c;
}

.row-line>div {
  width: 100%;
}

.col-line>div {
  height: 100%;
}